Evidence of a deep biological link between human music and speech has been found by Duke University neuroscientists.

They found that the musical scales most commonly used over the centuries are those that come closest to mimicking the physics of the human voice, and that we understand emotions expressed through music because the music mimics the way emotions are expressed in speech.

The showed that the harmonic structure of vowel tones forms the basis of the musical scales we find most appealing, and the popularity of musical scales can be predicted based on how well they match up with the series of harmonics characteristic of vowels in speech.